html,
body {
    box-sizing: border-box;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}


/* 屏幕不进行滚动 */

.flex-container {
    display: flex;
    display: -webkit-flex;
    display: -ms-flexbox;
    width: 100vw;
    height: 100vh;
    background-image: url('./images/bg2.jpg');
    background-color: #1e1e1e;
    background-repeat: no-repeat;
    background-size: 100% 100%;
    background-attachment: fixed;
}

header {
    width: 100%;
    height: 15vh;
    border: 1px saddlebrown solid;
    background-image: url(./images/title.png);
    background-repeat: no-repeat;
    background-size: 100% 100%;
}

header>nav>ul {
    width: 100%;
    height: 15vh;
}

header>nav>ul li {
    width: 15%;
    height: 100%;
    list-style: none;
    transform: translateY(30%);
    background-image: url(./images/menu_bg.png);
    background-repeat: no-repeat;
    background-position: left
}

header>nav>ul li:nth-of-type(1),
header>nav>ul li:nth-of-type(2) {
    float: left;
}

header>nav>ul li:nth-of-type(3),
header>nav>ul li:nth-of-type(4) {
    float: right;
}

header>nav>ul li img {
    transform: translate(20%, 20%)
}

header>nav>ul li.logo {
    width: 35%;
    background-image: url(./images/logo.png);
    background-size: 100%;
    background-repeat: no-repeat;
    transform: translateY(0%)
}

.xzzsa {
    animation: xzzsa 6s linear 0s normal none infinite;
    -moz-animation: xzzsa 6s linear 0s normal none infinite;
    /* Firefox */
    -webkit-animation: xzzsa 6s linear 0s normal none infinite;
    /* Safari 和 Chrome */
    -o-animation: xzzsa 6s linear 0s normal none infinite;
    /* Opera */
}

@keyframes xzzsa {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

@-moz-keyframes xzzsa
/* Firefox */

{
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

@-webkit-keyframes xzzsa
/* Safari 和 Chrome */

{
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

@-o-keyframes xzzsa
/* Opera */

{
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}